001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.io;
019
020import java.io.IOException;
021import java.util.Collections;
022import java.util.List;
023
024/**
025 * A IOException based on a list of Throwable causes.
026 * <p>
027 * The first exception in the list is used as this exception's cause and is accessible with the usual
028 * {@link #getCause()} while the complete list is accessible with {@link #getCauseList()}.
029 * </p>
030 *
031 * @since 2.7
032 */
033public class IOExceptionList extends IOException {
034
035    private static final long serialVersionUID = 1L;
036    private final List<? extends Throwable> causeList;
037
038    /**
039     * Creates a new exception caused by a list of exceptions.
040     *
041     * @param causeList a list of cause exceptions.
042     */
043    public IOExceptionList(final List<? extends Throwable> causeList) {
044        this(String.format("%,d exceptions: %s", causeList == null ? 0 : causeList.size(), causeList), causeList);
045    }
046
047    /**
048     * Creates a new exception caused by a list of exceptions.
049     *
050     * @param message The detail message, see {@link #getMessage()}.
051     * @param causeList a list of cause exceptions.
052     * @since 2.9.0
053     */
054    public IOExceptionList(final String message, final List<? extends Throwable> causeList) {
055        super(message, causeList == null || causeList.isEmpty() ? null : causeList.get(0));
056        this.causeList = causeList == null ? Collections.emptyList() : causeList;
057    }
058
059    /**
060     * Gets the cause exception at the given index.
061     *
062     * @param <T> type of exception to return.
063     * @param index index in the cause list.
064     * @return The list of causes.
065     */
066    public <T extends Throwable> T getCause(final int index) {
067        return (T) causeList.get(index);
068    }
069
070    /**
071     * Gets the cause exception at the given index.
072     *
073     * @param <T> type of exception to return.
074     * @param index index in the cause list.
075     * @param clazz type of exception to return.
076     * @return The list of causes.
077     */
078    public <T extends Throwable> T getCause(final int index, final Class<T> clazz) {
079        return clazz.cast(causeList.get(index));
080    }
081
082    /**
083     * Gets the cause list.
084     *
085     * @param <T> type of exception to return.
086     * @return The list of causes.
087     */
088    public <T extends Throwable> List<T> getCauseList() {
089        return (List<T>) causeList;
090    }
091
092    /**
093     * Works around Throwable and Generics, may fail at runtime depending on the argument value.
094     *
095     * @param <T> type of exception to return.
096     * @param clazz the target type
097     * @return The list of causes.
098     */
099    public <T extends Throwable> List<T> getCauseList(final Class<T> clazz) {
100        return (List<T>) causeList;
101    }
102
103}